1. Field of the Invention
The invention relates generally to attachments for conventional, trimmable, stern drive units, which include an external vertical drive portion drivingly interconnected with the engine of a power boat, and for conventional, tiltable outboard motors; and, more particularly, the invention relates to devices for augmenting, or enhancing, the drive trim capabilities of these two widely used types of power boat propulsion units.
2. Prior Art
The market-place is replete with various makes of"hydrofoils" which are designed for attachment to the anticavitation plate of these two main types of propulsion units. Typically, these "foils" are either planar or are somewhat downturned adjacent the trailing edge so as to increase hydrodynamic lift, thereby assisting in elevating the stern of the boat and facilitating getting the boat on plane. See, for example, Bass Pro Shops' 1996 Marine Catalog page 36.
Also available for purchase are trolling attachments which are pivotally mounted on the drive unit and can be selectively positioned either in a horizontal attitude, substantially coplanar with or parallel to the anticavitation plate, or in a vertical attitude in which the attachment receives the full impact of the propeller backwash, thereby retarding forward motion of the boat and, in effect, converting the drive unit to a trolling motor. Examples of such trolling attachments are disclose in Bass Pro Shops' 1996 Marine Catalog, page 36, and in U.S. Pat. No. 3,965,838, and U.S. No. 5,493,990, for example.